Incandescent filament and process.



UNITED STATES PATENT OFFICE.

EUGENE McOUriT, OF NEW YORK, N. Y., AND HENRY W, F. LORENZ, OF SPRINGFIELD, OHIO.

INCANDESCENT FILAMENT AND PROCESS.

Specification of Letters Patent.

Application filed December 6,1905. Serial No. 290,641-

Patented Oct. 22, 1907.

the United States, and a resident of Springfield, in the county of Clark and State of Ohio, have invented a new and Improved Incandescent Filament and Process, of which the following is a full, clear, and exact description. I

This invention relates to the manufacture of filaments or glowers such as used in incandescent electric lamps. The object of the invention is to produce a filament having high efiiciency and a long period of usefulness. The invention consists in the filament and in the process to be described more fully hereinafter and par ticularly set forth in the claims.

In preparing a filament according to our invention, we select a core such as a carbon filament, and coat the same with a mixture of silicon and metal, or metals. We prefer to apply this coat by preparing a caramel solution carrying this mixture of silicon and metal, or metals, in mechanical suspension. In this we dip the carbon filaments in such a way as to deposit a coat thereupon; the filaments then are baked so that the coat becomes dry and incorporated with the filament. This baking preferably takes place in an indifferent gas, and the temperature is raised to a point suiiiciently high to bring about a reaction between the silicon and the metal. In this way a silicid coated filament results. However, the silicid may be incorporated with the filament by other processes, such as the collodion process. This general process consists in dissolving cellulose such as cotton, in nitric acid, hydrochloric acid, or zinc chlorid and the plastic solution obtained is then forced through a die, hardened with alcohol, and

afterwards carbonized; according to our invention,

while the mass is in the plastic state, we mix with it a quantity of silicon and a metal, both in a finely divided state. The amount of silicon and metal added should be about 50 per cent of the plastic mass, but good results may be obtained with a preparation as low as ten per cent. All of the metals that have a high melting point may be used, except those of the platinum group. Metals which we have particularly in mind are thorium, tungsten, uranium, titanium, tantalum, niobium, vanadium, nickel, cobalt, molybdenum, manganese and chromium; all these metals" form silicids. The proportion of silicon to metal we find to he, is about 5 pcr.

Our silicid filament may be also made by an impregnation process, in which the entire core of the filament is impregnated with the silicid. In this instance we soak a carboniz'able thread in a mixture containing silicon and a metal, and afterward Carbonize and convert the silicon into a silicid by a high temperature.

Ins ead of using silicon and a metal in the process solution, we may use directly a silicid in that process, in which case we simply make the caramel solution in which a quantity of silicid is mixed, and the silicid is deposited directly upon the carbon cores by dipping them in the mixture. The filaments are afterwards baked in the usual manner'to harden the coat and carbonize the caramel solution with the silicid on the carbon core. Or, the filament of carbon can be flashed in a mixture of a volatile silicon and volatile metal compound, thus depositing silicon and metal simultaneously upon the carbon core. At a high temperature the n L silicon and carbon unite to form a silicid coat. The metal is preferably in the form of titanium tetramcthide having the formula Ti (CH molybdenum tetramcthid having the formula Mo.(CH the silicon maybe in the form of a tetramethid, Si-(CHQ, or in the form of a hydrid Si H c Having thus described our invention, wc'claim a new and desire to secure by Letters Patent 1. The process of making incandescent lamp filaments which consists in incorporating :1 metal and silicon in thc filament and forming a silicid by reaction hchvccn the metal and the silicon components.

2. The process of making incamlcsccnt lump tilznncnls which consists in incorporating; a metal and silicon in the filament. and heating said filamentthereafter to comhinc the silicon and mctal.

.l. The process of making incandescent filaments which consists in depositing u metal and silicon on the surface of a core and effecting the formation of n silicid by heat.

4. The process of making incandescent filznncnis which consists in producing u (out on :1 core. said coat consisting of n cnrlmnlznhlc hinder having particles of finely divided mclnl nnd silicon in mechanical suspension lhcrein. \vhcrcby salid'meinl and silicon adheres to snirl core. and forming-2n silicid and cnrhonlzing suld hinder by heat.

5. As new article of nnnnnm'turc. :in incandescent lump iilumcut having a carbonized body with u sllicirl incorporated ihcrcwiih.

1'. An incandescent himp filament havinga sllh-id us :1 lls'hl omitting substance.

in testimony whcrcol' \vc lune signed our names to this specification in lllc pl'cscncc of two subscribing \vilncsscs.

Witnesses us 40 the slgnnlure of Henry \V. F. Lorrnz: .l 1G. L'UNh'LlN.

Maura Loni-:Nz. 

